Spending a lot of money and building a show car is one thing, to try and make a bad handling and not that quick car as standard by spending £2k to me is pointless, starting with a mk2 would be a better bet as it lighter.
This is where you are showing your ignorance...
Mk3 isn't much heavier than a late Mk2 when you get them lightened a bit...and with a significantly stronger 'shell, you end up with a stiffer platform to mount the suspension.
Take both to the extreme, and the weights will be similar...Mk2 needs more of a cage as the base shell os not as stiff (more weight) but Mk3 has wider track. Road car vs road car...the lighter Mk2 vs stiffer Mk3 with better brakes.
I was quicker round Knockhill in my Mk3 8v than my mate in his Mk2 16v (both road cars...both on uprates suspension and wheels/tyres)
So you take a heavy, ill handling Mk3 and spend a few £1000 wisely and you will be bang on Mk2 pace...
The Mk2 accellerates quicker, the Mk3 brakes better.
Can you tell me why a Corrado VR6 handles better than a Mk3 VR6?
It's not much...I can assure yoiu...minor tweak that turns a turd into one of the best handling FWD cars ever.